build: adopt @fluidframework/eslint-config-fluid v9.0.0

brainstorm/eslint.config.mts

@@ -0,0 +1,44 @@
+import { recommended } from "@fluidframework/eslint-config-fluid/flat.mjs";
+
+export default [
+	...recommended,
+	{
+		rules: {
+			// Example apps use sub-path imports (e.g. "@fluidframework/odsp-client/beta")
+			// and relative imports with extensions, which this rule disallows.
+			"import-x/no-internal-modules": "off",
+
+			// Explicit return types add verbosity that hurts readability in example code.
+			"@typescript-eslint/explicit-function-return-type": "off",
+			"@typescript-eslint/explicit-module-boundary-types": "off",
+
+			// Existing files use snake_case naming; renaming would break imports across the project.
+			"unicorn/filename-case": "off",
+
+			// Allow == null checks which cover both null and undefined.
+			eqeqeq: ["error", "smart"],
+
+			// Common variable naming patterns in React code and callback-heavy code.
+			"@typescript-eslint/no-shadow": "off",
+
+			// Example code interacts with external APIs (Microsoft Graph, MSAL) that
+			// return loosely-typed data. Suppressing these keeps focus on the Fluid patterns.
+			"@typescript-eslint/no-unsafe-assignment": "off",
+			"@typescript-eslint/no-unsafe-member-access": "off",
+			"@typescript-eslint/no-unsafe-argument": "off",
+			"@typescript-eslint/strict-boolean-expressions": "off",
+
+			// Some transitive deps are used directly in examples.
+			"import-x/no-extraneous-dependencies": "off",
+
+			// CSS side-effect imports are expected.
+			"import-x/no-unassigned-import": "off",
+
+			// null is used by external APIs and React patterns.
+			"unicorn/no-null": "off",
+
+			// Top-level await doesn't work in all bundler configurations.
+			"unicorn/prefer-top-level-await": "off",
+		},
+	},
+];